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== Abuse when used for ocular pain relief ==
== Abuse when used for ocular pain relief ==


When used excessively, topical anesthetics can cause severe and irreversible damage to corneal tissues<ref name="Pharmakakis">Pharmakakis NM, Katsimpris JM, Melachrinou MP, Koliopoulos JX. "Corneal complications following abuse of topical anesthetics." ''Eur J Ophthalmol.'' 2002 Sep-Oct;12(5):373-8. PMID 12474918.</ref><ref name="Varga">Varga JH, Rubinfeld RS, Wolf TC, Stutzman RD, Peele KA, Clifford WS, Madigan W. "Topical anesthetic abuse ring keratitis: report of four cases." ''Cornea.'' 1997 Jul;16(4):424-9. PMID 9220240</ref><ref name="Chern">Chern KC, Meisler DM, Wilhelmus KR, Jones DB, Stern GA, Lowder CY. "Corneal anesthetic abuse and Candida keratitis." ''Ophthalmology.'' 1996 Jan;103(1):37-40. PMID 8628558.</ref><ref name="Ardjomand">Ardjomand N, Faschinger C, Haller-Schober EM, Scarpatetti M, Faulborn J. "[A clinico-pathological case report of necrotizing ulcerating keratopathy due to topical anaesthetic abuse]." ''Ophthalmologe.'' 2002 Nov;99(11):872-5. PMID 12430041.</ref><ref name="Chen">Chen HT, Chen KH, Hsu WM. "Toxic keratopathy associated with abuse of low-dose anesthetic: a case report." ''Cornea.'' 2004 Jul;23(5):527-9. PMID 15220742.</ref> and even loss of the eye.<ref name="Rosenwasser">Rosenwasser GO, Holland S, Pflugfelder SC, Lugo M, Heidemann DG, Culbertson WW, Kattan H. "Topical anesthetic abuse." ''Ophthalmology.'' 1990 Aug;97(8):967-72. PMID 2402423</ref> The abuse of topical anesthetics often creates challenges for correct diagnosis in that it is a relatively uncommon entity that may initially present as a chronic [[keratitis]] masquerading as [[acanthamoeba keratitis]] or other [[infectious keratitis]].<ref name="Pharmakakis"/><ref name="Varga"/><ref name="Ardjomand"/><ref name="Rosenwasser"/><ref name="Sun">Sun MH, Huang SC, Chen TL, Tsai RJ. "Topical ocular anesthetic abuse: case report." ''Chang Gung Med J.'' 2000 Jun;23(6):377-81. PMID 10958042</ref> When a keratitis is unresponsive to treatment and associated with strong ocular pain, topical anesthetic abuse should be considered,<ref name="Ardjomand"/> and a history of psychiatric disorders and other substance abuse have been implicated as important factors in the diagnosis.<ref name="Pharmakakis"/><ref name="Rosenwasser"/><ref name="Sun"/> Because of the potential for abuse, clinicians have been warned about the possibility of theft and advised against prescribing topical anesthetics for therapeutic purposes.<ref name="Varga"/><ref name="Rosenwasser"/>
When used excessively, topical anesthetics can cause severe and irreversible damage to corneal tissues<ref name="Pharmakakis">{{cite journal |author=Pharmakakis NM, Katsimpris JM, Melachrinou MP, Koliopoulos JX |title=Corneal complications following abuse of topical anesthetics |journal=Eur J Ophthalmol |volume=12 |issue=5 |pages=373–8 |year=2002 |pmid=12474918 }}</ref><ref name="Varga">{{cite journal |author=Varga JH, Rubinfeld RS, Wolf TC, ''et al.'' |title=Topical anesthetic abuse ring keratitis: report of four cases |journal=Cornea |volume=16 |issue=4 |pages=424–9 |year=1997 |month=July |pmid=9220240 |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0277-3740&volume=16&issue=4&spage=424}}</ref><ref name="Chern">{{cite journal |author=Chern KC, Meisler DM, Wilhelmus KR, Jones DB, Stern GA, Lowder CY |title=Corneal anesthetic abuse and Candida keratitis |journal=Ophthalmology |volume=103 |issue=1 |pages=37–40 |year=1996 |month=January |pmid=8628558 }}</ref><ref name="Ardjomand">{{cite journal |author=Ardjomand N, Faschinger C, Haller-Schober EM, Scarpatetti M, Faulborn J |title=[A clinico-pathological case report of necrotizing ulcerating keratopathy due to topical anaesthetic abuse] |language=German |journal=Ophthalmologe |volume=99 |issue=11 |pages=872–5 |year=2002 |month=November |pmid=12430041 |doi=10.1007/s00347-002-0623-z }}</ref><ref name="Chen">{{cite journal |author=Chen HT, Chen KH, Hsu WM |title=Toxic keratopathy associated with abuse of low-dose anesthetic: a case report |journal=Cornea |volume=23 |issue=5 |pages=527–9 |year=2004 |month=July |pmid=15220742 |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0277-3740&volume=23&issue=5&spage=527}}</ref> and even loss of the eye.<ref name="Rosenwasser">{{cite journal |author=Rosenwasser GO, Holland S, Pflugfelder SC, ''et al.'' |title=Topical anesthetic abuse |journal=Ophthalmology |volume=97 |issue=8 |pages=967–72 |year=1990 |month=August |pmid=2402423 }}</ref> The abuse of topical anesthetics often creates challenges for correct diagnosis in that it is a relatively uncommon entity that may initially present as a chronic [[keratitis]] masquerading as [[acanthamoeba keratitis]] or other [[infectious keratitis]].<ref name="Pharmakakis"/><ref name="Varga"/><ref name="Ardjomand"/><ref name="Rosenwasser"/><ref name="Sun">{{cite journal |author=Sun MH, Huang SC, Chen TL, Tsai RJ |title=Topical ocular anesthetic abuse: case report |journal=Chang Gung Med J |volume=23 |issue=6 |pages=377–81 |year=2000 |month=June |pmid=10958042 }}</ref> When a keratitis is unresponsive to treatment and associated with strong ocular pain, topical anesthetic abuse should be considered,<ref name="Ardjomand"/> and a history of psychiatric disorders and other substance abuse have been implicated as important factors in the diagnosis.<ref name="Pharmakakis"/><ref name="Rosenwasser"/><ref name="Sun"/> Because of the potential for abuse, clinicians have been warned about the possibility of theft and advised against prescribing topical anesthetics for therapeutic purposes.<ref name="Varga"/><ref name="Rosenwasser"/>


Some patients who suffer from eye pain, which is often considerably strong [[neuropathic pain]] caused by the irritation of the nerves within the cornea and/or conjunctiva, unfortunately try to illegally obtain oxybuprocaine or other eye anesthetics (for example by [[Theft|stealing]] them at their [[ophthalmologist]] or [[optometrist]], by [[Forgery|forging]] [[medical prescription]]s or by trying to order it via an [[online pharmacy]]) and secretly use the substance to numb their eye pain, often ending up with irreversible corneal damage or even destruction (which is a [[vicious cycle]] and causes even much more pain). Often, such patients finally require [[Cornea transplant|corneal transplantation]].
Some patients who suffer from eye pain, which is often considerably strong [[neuropathic pain]] caused by the irritation of the nerves within the cornea and/or conjunctiva, unfortunately try to illegally obtain oxybuprocaine or other eye anesthetics (for example by [[Theft|stealing]] them at their [[ophthalmologist]] or [[optometrist]], by [[Forgery|forging]] [[medical prescription]]s or by trying to order it via an [[online pharmacy]]) and secretly use the substance to numb their eye pain, often ending up with irreversible corneal damage or even destruction (which is a [[vicious cycle]] and causes even much more pain). Often, such patients finally require [[Cornea transplant|corneal transplantation]].

Revision as of 08:36, 12 March 2012

A topical anesthetic is a local anesthetic that is used to numb the surface of a body part. They can be used to numb any area of the skin as well as the front of the eyeball, the inside of the nose, ear or throat, the anus and the genital area.[1] Topical anesthetics are available in creams, ointments, aerosols, sprays, lotions, and jellies.[2] Examples include benzocaine, butamben, dibucaine, lidocaine, oxybuprocaine, pramoxine, proparacaine, proxymetacaine, and tetracaine (also named amethocaine).

Usage

Topical anesthetics are used to relieve pain and itching caused by conditions such as sunburn or other minor burns, insect bites or stings, poison ivy, poison oak, poison sumac, and minor cuts and scratches.[2]

Topical anesthetics are used in ophthalmology and optometry to numb the surface of the eye (the outermost layers of the cornea and conjunctiva) to:

  • Perform a contact/applanation tonometry.
  • Perform a Schirmer's test (The Schirmer's test is sometimes used with a topical eye anesthetic, sometimes without. The use of a topical anesthetic might impede the reliability of the Schirmer's test and should be avoided if possible.).
  • Remove small foreign objects from the uppermost layer of the cornea or conjunctiva. The deeper and the larger a foreign object which should be removed lies within the cornea and the more complicated it is to remove it, the more drops of topical anesthetic are necessary prior to the removal of the foreign object to numb the surface of the eye with enough intensity and duration.

In dentistry, topical anesthetics are used to numb oral tissues before administering a dental local anesthetic.

Some topical anesthetics (e.g. oxybuprocaine) are also used in otolaryngology.

Topical anesthetics are now commonly used in the temporary relief of premature ejaculation when applied to the Glans (head) of the penis. Benzocaine or lidocaine are typically used for this purpose as they are available OTC (lidocaine is more powerful than benzocaine).

Duration of topical

The duration of topical anesthesia might depend on the type and amount applied, but is usually about half an hour.[citation needed]

Abuse when used for ocular pain relief

When used excessively, topical anesthetics can cause severe and irreversible damage to corneal tissues[3][4][5][6][7] and even loss of the eye.[8] The abuse of topical anesthetics often creates challenges for correct diagnosis in that it is a relatively uncommon entity that may initially present as a chronic keratitis masquerading as acanthamoeba keratitis or other infectious keratitis.[3][4][6][8][9] When a keratitis is unresponsive to treatment and associated with strong ocular pain, topical anesthetic abuse should be considered,[6] and a history of psychiatric disorders and other substance abuse have been implicated as important factors in the diagnosis.[3][8][9] Because of the potential for abuse, clinicians have been warned about the possibility of theft and advised against prescribing topical anesthetics for therapeutic purposes.[4][8]

Some patients who suffer from eye pain, which is often considerably strong neuropathic pain caused by the irritation of the nerves within the cornea and/or conjunctiva, unfortunately try to illegally obtain oxybuprocaine or other eye anesthetics (for example by stealing them at their ophthalmologist or optometrist, by forging medical prescriptions or by trying to order it via an online pharmacy) and secretly use the substance to numb their eye pain, often ending up with irreversible corneal damage or even destruction (which is a vicious cycle and causes even much more pain). Often, such patients finally require corneal transplantation.

In case of prolonged or chronic eye pain, especially neuropathic eye pain, it is highly advisable to use centrally acting substances like anticonvulsants (pregabalin, gabapentin and in more serious cases carbamazepine) or antidepressants (for example SSRIs or the tricyclic antidepressant amitriptyline). Even very small amounts of an anticonvulsant and/or an antidepressant can almost completely stop eye pain and does not damage the eye at all.

See also

Notes

  1. ^ Healthopedia.com
  2. ^ a b MedlinePlus[dead link]
  3. ^ a b c Pharmakakis NM, Katsimpris JM, Melachrinou MP, Koliopoulos JX (2002). "Corneal complications following abuse of topical anesthetics". Eur J Ophthalmol. 12 (5): 373–8. PMID 12474918.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  4. ^ a b c Varga JH, Rubinfeld RS, Wolf TC; et al. (1997). "Topical anesthetic abuse ring keratitis: report of four cases". Cornea. 16 (4): 424–9. PMID 9220240. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  5. ^ Chern KC, Meisler DM, Wilhelmus KR, Jones DB, Stern GA, Lowder CY (1996). "Corneal anesthetic abuse and Candida keratitis". Ophthalmology. 103 (1): 37–40. PMID 8628558. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  6. ^ a b c Ardjomand N, Faschinger C, Haller-Schober EM, Scarpatetti M, Faulborn J (2002). "[A clinico-pathological case report of necrotizing ulcerating keratopathy due to topical anaesthetic abuse]". Ophthalmologe (in German). 99 (11): 872–5. doi:10.1007/s00347-002-0623-z. PMID 12430041. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  7. ^ Chen HT, Chen KH, Hsu WM (2004). "Toxic keratopathy associated with abuse of low-dose anesthetic: a case report". Cornea. 23 (5): 527–9. PMID 15220742. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  8. ^ a b c d Rosenwasser GO, Holland S, Pflugfelder SC; et al. (1990). "Topical anesthetic abuse". Ophthalmology. 97 (8): 967–72. PMID 2402423. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  9. ^ a b Sun MH, Huang SC, Chen TL, Tsai RJ (2000). "Topical ocular anesthetic abuse: case report". Chang Gung Med J. 23 (6): 377–81. PMID 10958042. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
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